Book Review

Norman Herz

The Fogg Art Museum once published a quarterly journal, “Technical Studies in the Field of Fine Arts,” from July 1932 to April 1942, that was designed to reach out to art historians, conservation scientists, and conservators. It did much to expand interest in interdisciplinary activities related to the study of Fine Arts. Unfortunately today, no current periodical appears to address such a broad field of interest. Even though interdisciplinary interests must be at an all-time high, most publications have become very narrowly focused. As an exception to these publications and an example of this great interest, the Boston Museum of Fine Arts held a symposium in September, 1983, on Applications of Science in Examination of Works of Art. Reports were presented of analyses from mass spectrometry to dendrochronology carried out on works of art which ranged from ancient Chinese bronzes to Filippino Lippi. The papers were by scientists and conservators who were working closely with art historians and archaeologists. This monograph on the stone sculpture of India and others to follow, we are promised, is an attempt to continue the close relationships between scientists and conservators once fostered by “Technical Studies.”

Throughout Indian history, beginning with Ashoka (273-232 B.C.), a great variety of stones was used in sculpture and architecture. Compared to the ancient Greeks and Romans, marble was not the universally used material, probably because of overland transportation problems and its restricted occurrence, but rather any attractive and durable stone that was available locally was used. Despite a great variety, museum catalogues and other publications generally either ignore or incorrectly describe the stone of an artifact. In this work, 187 samples of Indian sculpture, dating from the 2nd century B.C. to the 16th A.D. were examined by standard petrographic and chemical methods. The aims of the study were to

identify as precisely as possible the varieties of rock using a geologically correct nomenclature;

point out possible quarry sources for the individual samples using their precise petrographic decriptions and comparing them to published geological reports of local areas;

determine the value of petrographic studies in establishing the provenance of Indian sculpture.

Curators and art historians need information on the nature of the stone comprising the artifact. The first step in assigning provenance must be to identify correctly the material comprising the object in question. In addition, a study of the rock types used by sculptors would lead to a better understanding of their technical skills and the interaction of specific rocks and their styles. Considering the enormous period of time involved in this study, almost 2,000 years, and the great area covered, the number of samples studied, 187, is embarrassingly small. However, by comparison to the local geology, the author feels that the principal rocks of the major schools are represented. Certainly, more sampling might reveal the use of other rock types, and future studies should be carried out to ascertain these types.

The samples studied came from nine museum and private collections from throughout the United States, largely obtained from undocumented sites. However, all the objects had been assigned to specific periods and areas on stylistic grounds. Since the sources of the material were presumed to be local, by comparison to published geological information the provenance of the stones could be assigned. Where the regional geology allowed more than one source, all the possibilities are listed.

Precise rock names necessitate the use of technical geological terms that are generally unrecognizable to a non-geologist. The author feels that these terms are not needed in most cases, but some geological background is necessary to classify rocks by any system. Thus the paper is presented at two levels: one which gives the precise technical geological terminology and a second which uses general terms that should be recognizable with a minimum of geological training. Section 2, “General Introduction to Geological Terms,” provides this training for the non-geologist. This section defines the simplified name system used in the book. Many of the terms will be new for most curators and art historians but they should be learned and used for Indian as well as any other stone sculpture. Certainly, most of the classifications now used to describe stone sculpture are highly subjective as well as incorrect. Geologically correct descriptions of objects in collections will connote a precise picture and have the same meaning to all persons; that in itself would be a major contribution to art history and conservation.

Chapter 3 reviews the geology and geography and chapter 4 the principal rock formations of India for the non-geologist. Plate tectonic history is also illustrated, starting some 140 million years ago when India was part of the Gondwana continent (named after the Gonds, a primitive tribe of Central India). At that time, before continental break-up and its flight to collide with Asia, India was neatly in tucked between Africa, Antarctica, and Australia. A higher level of information is given in the appendix where the geological history is given in more detail and lithologic units are described more precisely.

Chapter 5 is a description of sampling techniques and analytical procedures. Samples, most about 1 × 1 × 0.2–0.5 cm, were collected with chisels and hammer. From these, thin sections were cut for petrographic analysis: mineral identification and rock textures. Chemical analysis by scanning electron microscope, emission spectrography and electron microprobe as well as x-ray diffraction for mineral identification were also carried out. Appendix A gives detailed descriptions, with tables and illustrations, of the petrographic techniques and results. Since this report is intended to teach (and proselytize), chemical compositions of the minerals should have been given. This is especially important to make the mineral variation diagrams more meaningful for non-geologists. If end member chemical compositions, for example, had been shown for the pyroxenes, then compositions of intermediate members, as eulite, salite, etc. would have become apparent both in the diagrams and in the text.

The author assembles enough chemical, mineralogical, and textural information to classify the rocks by any recognized petrographic method. The samples are tabulated together with their rock types, shown with a general name and petrographic description. Typical thin sections, in plain and polarized light, are illustrated—a pity that they could not be shown in color! The descriptive tables are given in the appropriate sections as well as tabulated together in an appendix. They are well done and should be a good model for curators to follow in preparing descriptions of stone sculpture anywhere.

The major part of the book is a detailed description of the sources of rock to be found in each region of India: Southern, Northeastern, Central and Northern, and Gandhara (northwestern India-northern Pakistan-Afghanistan). The sections are profusely illustrated with examples of sculpture and geological maps showing the areas underlain by each rock type. The reader can thus easily see the potential source areas and the rationale for assigning provenance for each sample.

The tabulation by region leads to some interesting conclusions about the rock types used and their period of use. For example, sandstone appears to have been most popular in Central India, but in other regions, a great variety of metamorphic rocks were used. All the sculptural stones, however, were available locally.

In Karnataka, in the western part of South India, metamorphosed ultramafic rocks were used in the Hoysala period. In the Western Chalukya period, metasiltstone and metaultramafics were used. The Palavas and Cholas, in Tamil Nadu in eastern South India, quarried granulites and charnockites for sculpture. The Vindhyan Mountains of Central India are underlain by sandstone and quartzite which provided the sculptural materials for Sanchi and Khajuraho. From this compendium, it can be seen that in many cases, the knowledge of local Indian geology can help assign a provenance to sculpture of unknown origin.

As a first step in showing the value of detailed petrographic descriptions for sourcing, the book has succeeded admirably. Ideally, such studies should begin with objects of known provenance to help establish a data base for each time period and region. Although this study did not have enough samples to establish itself as a definitive work, it does succeed both as a model for future investigations as well as a lexicon and guide for conservators and art historians working with any stone materials. Simple but accurate petrographic descriptions should always be the first step in attempting assignments of provenance or of association of broken fragments. More sophisticated techniques, such as stable isotopic, major element, or trace element analysis can also help, if the problem warrants and the necessary data base exists.

The book can serve various purposes: to show the impact of stone materials on sculpture, to show the uses of geological maps and reports for provenance studies, and to instruct curators, conservators, and art historians in terminology that will eliminate subjective descriptions for stone sculpture. When correct decriptions become the norm rather than the exception, more meaningful comparisons, as done for association of broken fragments, will be possible.

The book is well illustrated, both from a sculptural and geological point of view, with a clear, well-written, and concise text, so it can be recommended from a layman non-professional, “coffee-table” point of view. It can be even more highly recommended to professionals as a source of information about Indian sculpture and as model for future studies of stone sculpture. It is an important contribution to the renewed and vitalic interdisciplinary field of science applied to works of art.